Simple Interest
Math MCQs

Question :    Calculate the amount due if Patricia borrowed a sum of $3150 at 6% simple interest for 3 years.

Correct Answer  $3717

Solution & Explanation

Solution

Given,

Principal (P) = $3150

Rate of Simple Interest (SI) = 6%

Time (t) = 3 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% per annum.

Method (1) Using Formula

Calculation of Simple Interest

Formula to Calculate Simple Interest

Simple Interest (SI) = Principal × Rate × Time

Thus, Simple Interest (SI) = $3150 × 6% × 3

= $3150 ×⁶/₁₀₀ × 3

= ^{3150 × 6 × 3}/₁₀₀

= ^{18900 × 3}/₁₀₀

= ⁵⁶⁷⁰⁰/₁₀₀

= $567

Thus, Simple Interest = $567

Calculation of Amount

The total money paid to the lender by a borrower is called the Amount.

In other words, sum of priciple and interest is called the Amount.

Formula to Calculate the Amount

Amount = Principal + Interest

Thus, Amount = $3150 + $567

= $3717

Thus, Amount to be paid = $3717 Answer

Method (2)

Calculation of Amount when Principal, Rate of Simple Interest and Time are given

Calculation of Amount directly using Principal, SI, and Time

Formula to calculate the Amount

Amount (A) = Principal (P) + Principal(P) × Rate of Interest (SI) × Time (t)

⇒ A = P + PRT

Here in the question, P = $3150

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 3 years

Thus, Amount (A)

= $3150 + ($3150 × 6% × 3)

= $3150 + ($3150 ×⁶/₁₀₀ × 3)

= $3150 + (^{3150 × 6 × 3}/₁₀₀)

= $3150 + (^{18900 × 3}/₁₀₀)

= $3150 + (⁵⁶⁷⁰⁰/₁₀₀)

= $3150 + $567 = $3717

Thus, Amount (A) to be paid = $3717 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $3150, the simple interest in 1 year

= ⁶/₁₀₀ × 3150

= ^{6 × 3150}/₁₀₀

= ¹⁸⁹⁰⁰/₁₀₀ = $189

Thus, simple interest for 1 year = $189

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $189 × 3 = $567

Thus, Simple Interest (SI) = $567

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3150 + $567

= $3717

Thus, Amount to be paid = $3717 Answer

Similar Questions

(1) How much loan did Lisa borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6655 to clear it?

(2) What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 4% simple interest?

(3) Calculate the amount due if Christopher borrowed a sum of $4000 at 8% simple interest for 3 years.

(4) Nancy took a loan of $6300 at the rate of 6% simple interest per annum. If he paid an amount of $10080 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 9% simple interest.

(6) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 4% simple interest?

(7) How much loan did Jason borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8470 to clear it?

(8) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 9% simple interest for 7 years.

(9) Sarah took a loan of $5700 at the rate of 8% simple interest per annum. If he paid an amount of $8892 to clear the loan, then find the time period of the loan.

(10) Anthony had to pay $4558 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.